Post on 30-Dec-2015
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Chapter 6Storage41 slides
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Chapter 6 Objectives
Describe the characteristics ofmagnetic disks
Describe the characteristics ofmagnetic disks
Describe the characteristics of a hard disk
Describe the characteristics of a hard disk
Differentiate between floppy disks and Zip disks
Differentiate between floppy disks and Zip disks
Describe the characteristics of optical disks
Describe the characteristics of optical disks
Differentiate among various CD and DVD formats
Differentiate among various CD and DVD formats
Identify the uses of tapeIdentify the uses of tape
Discuss PC Cards and the various typesof miniature mobile storage media
Discuss PC Cards and the various typesof miniature mobile storage media
Identify uses of microfilm and microfiche
Identify uses of microfilm and microfiche
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Storage
What is storage?
p. 220 - 221 Fig. 6-1 Next
Holds data, instructions, and information for future use Storage medium is physical material used for storage
Also called secondary storage
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Storage
What is capacity?
p. 222 Next
Kilobyte (KB) 1 thousand
Megabyte (MB) 1 million
Gigabyte (GB) 1 billion
Terabyte (TB) 1 trillion
Petabyte (PB) 1 quadrillion
Number of bytes (characters) a storage medium can hold
Exabyte (EB) 1 quintillion
Zettabyte (ZB) 1 sextillion
Yottabyte (YB) 1 septillion
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WritingWritingProcess of transferring Process of transferring
items from memory items from memory to storage mediato storage media
WritingWritingProcess of transferring Process of transferring
items from memory items from memory to storage mediato storage media
Storage
What is a storage device?
p. 222
ReadingReadingProcess of transferring Process of transferring
items from storage items from storage media to memorymedia to memory
ReadingReadingProcess of transferring Process of transferring
items from storage items from storage media to memorymedia to memory
Hardware that Hardware that records and records and
retrieves items retrieves items to and from to and from
storage mediastorage media
Functions as source of input
Creates output
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Storage
What is access time?
p. 222
Time it takes storage device to locate item on storage medium
Time required to deliver item from memory to processor
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Magnetic Disks
p. 222 Fig. 6-3 Next
What are tracks and sectors?
Formatting prepares disk for use and marks bad sectors as unusable
Trackis narrow
recording bandthat forms fullcircle on disk
Sector stores up to512 bytes
of data
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Perpendicular recording
Magnetic Disks
What is a hard disk?
p. 223 Fig. 6-4 Next
hard disk installedin system unit
High-capacity storage Consists of several
inflexible, circular platters that store items electronically
Components enclosed in airtight, sealed case for protection
Click to view Web Link,click Chapter 6, Click Web Linkfrom left navigation, then click Perpendicular Recording below Chapter 6
Longitudinal recording
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Magnetic Disks
What are characteristics of a hard disk?
p. 224 Fig. 6-5 Next
Sample Hard Disk Characteristics
Advertised capacity 120 GB
Platters 3
Read/write heads 6
Cylinders 16,383
Bytes per second 512
Sectors per track 63
Sectors per drive 234,441,648
Revolutions per minute 7,200
Transfer rate 133 MB per second
Access time 8.9 ms
actualdisk
capacity
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Magnetic Disks
How does a hard disk work?
p. 224 Fig. 6-6 Next
Step 1.Circuit board controls movement of head actuator and a small motor.
Step 2.Small motor spins platters while computer is running.
Step 3.When software requests a disk access, read/write heads determine current or new location of data.
Step 4.Head actuator positions read/write head arms over correct location on platters to read or write data.
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Video: Install a New Hard Drive
Speed up your computer with a new hard drive
low quality(click to start)
high quality(click to start)
Next
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Magnetic Disks
What is a cylinder?
p. 225 Fig. 6-7 Next
Vertical section of track through all platters
Single movement of read/write head arms accesses all plattersin cylinder
platter
read/writehead
platter
sides
cylinder
track
sector
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Magnetic Disks
What is a head crash?
p. 225 Fig. 6-8 Next
clearance
read/write head
platter
hair
dustsmoke
Spinning creates cushion of air that floats read/write head above platter
Occurs when read/write head touches platter surface
A smoke particle, dust particle, or human hair could render drive unusable
Clearance between head and platter is approximately two-millionths of an inch
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Magnetic Disks
What is a miniature hard disk?
p. 226 Fig. 6-9
Provide users with greater storage capacities than flash memory Some have a form factor of less than 1 inch Storage capacities range from 2 GB to 120 GB
Click to view Web Link,click Chapter 6, Click Web Linkfrom left navigation, then click Miniature Hard Disksbelow Chapter 6
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Magnetic Disks
What are external hard disks and removable hard disks?
p. 226 Fig. 6-10 Next
External hard disk—freestandinghard disk that connects to system unit
Removable hard disk—hard diskthat you insert and removefrom hard disk drive
Used to back up or transfer files
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SCSISCSI((SSmallmall CComputeromputer SSystemystem IInterface)nterface)
controller supports up to fifteencontroller supports up to fifteendevices including hard disks, CDdevices including hard disks, CD
and DVD drives, tape drives, printers,and DVD drives, tape drives, printers,scanners, network cardsscanners, network cards
SATASATA (Serial Advanced Serial Advanced Technology AttachmentTechnology Attachment) controller ) controller
uses serial signals to transfer data, uses serial signals to transfer data, instructions, and informationinstructions, and information
Magnetic Disks
What is a disk controller?
p. 226 - 227 Next
EIDEEIDE (EEnhancednhanced IIntegratedntegrated DDrive rive EElectronics) controller supports four lectronics) controller supports four hard disks, provides connections for hard disks, provides connections for
CD and DVD drivesCD and DVD drives
Chip and circuits that Chip and circuits that control transfer of control transfer of items from diskitems from disk
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Magnetic Disks
What is online storage?
p. 227 Fig. 6-11 Next
Others can be authorized to access your data
Service on Web that provides storage for minimal monthly fee
Files can be accessed from any computer with Web access
Large files can be downloaded instantaneously
Click to view Web Link,click Chapter 6, Click Web Linkfrom left navigation, then click Online Storagebelow Chapter 6
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Magnetic Disks
What is a floppy disk?
p. 228
Portable, inexpensive storage medium (also called diskette)
Thin, circular, flexible film enclosedin 3.5” wide plastic shell
shutter
shell
liner
magneticcoating
flexible thin film
metal hub
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Magnetic Disks
What is a floppy disk drive?
p. 228 Fig. 6-12 Next
Floppy disk drive built intoa desktop computer
External floppy disk drive attaches to a computer with a cable
Also called secondary storage
One floppy drive, named drive A
Device that reads from andwrites to floppy disk
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Magnetic Disks
What is a Zip disk?
p. 228 Fig. 6-13 Next
Magnetic medium that stores 100 MB to 750 MB of data
Zip disks require a Zip drivec—chigh capacity drive that reads from and writes on a Zip disk
Used to back up and to transfer files Backup is duplicate of file, program, or disk
in case original is lostc
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Push the same buttonto close the tray.
Optical Discs
What are optical discs?
p. 229 Fig. 6-14 Next
Most PCs include an optical disc drive
Flat, round, portable metal discs made of metal, plastic, and lacquer
Can be read only or read/write
Insert the disc,label side up.
Push the button toslide out the tray.
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Optical Discs
How should you care for an optical disc?
p. 230 Fig. 6-15 Next
Do store thedisc in a jewelbox whennot in use
Do hold a discby its edges
Do noteat, smoke, ordrink neara disc
Do not stack discs
Do not exposethe disc to excessiveheat or sunlight
Do not touchthe undersideof the disc
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Optical Discs
What is a CD-ROM?
p. 231 Fig. 6-17 Next
Compact disc read-only memory
Cannot erase or modify contents Typically holds 650 MB to 1 GB Commonly used to distribute multimedia and complex software
Click to view Web Link,click Chapter 6, Click Web Linkfrom left navigation, then click CD-ROMsbelow Chapter 6
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Optical Discs
What is a Picture CD?
p. 232 Fig. 6-18 Next
Film developers offer
Picture CD service
Can be modified
using photo editing software
Stores digital versions of roll of film
Step 3.At home, print images from Picture CD on your ink-jet photo printer.
At a store, print images to Picture CD at kiosk.
Step 1.Drop off film to be developed. Mark the Picture CD box on the film-processing envelope.
Step 2.When you pick up prints and negatives, a Picture CD contains digital images of each photograph.
Click to view Web Link,click Chapter 6, Click Web Linkfrom left navigation, then click Picture CDs below Chapter 6
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Optical Discs
What are CD-Rs and CD-RWs?
p. 232 Next
Must haveCD recorder
or CD-R drive
Cannot erasedisc’s contents
CD-R (compact disc-recordable)—cdisc you can write on once
CD-RW (compact disc-rewritable)—ceerasable disc you can write on
multiple times
Must haveCD-RW softwareand CD-RW drive
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Optical Discs
What is a DVD-ROM (digital versatile disc-ROM or digital video disc-ROM)?
p. 233 Fig. 6-19 Next
Must have DVD-ROM drive or DVD player to read DVD-ROM
Stores databases, music, complex software, and movies
Blu-ray discs have storage capacity of up to 27 GB
HD-DVD discs have storage capacity of up to 45 GB
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Optical Discs
How does a DVD-ROM store data?
p. 233 Fig. 6-20 Next
Two layers of pits are used, lower layer is semitransparent so laser can read through
Some are double-sided Many types of recordable and rewritable DVDs are
available DVD-R and DVD+R DVD-RW and DVD+RW
Click to view Web Link,click Chapter 6, Click Web Linkfrom left navigation, then click DVDsbelow Chapter 6
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Tape
What is tape?
p. 234 Fig. 6-21 Next
Magnetically coated plastic ribboncapable of storing large amountsof data at low cost
Primarily used for backup
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Tape
How is data stored on a tape?
p. 234 - 235 Next
Sequential access
Unlike direct access — used on floppy disks, Zip disks, hard disks, CDs, and DVDs — which can locate particular item immediately
Reads and writes data consecutively, like music tape
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PC Cards
What is a PC Card?
p. 235 Figs. 6-22–6-23 Next
Adds capabilities to computer Credit-card-sized device
commonly used in notebook computers
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Miniature Mobile Storage Media
What is miniature mobile storage media?
p. 236 Fig. 6-24 Next
Storage for small mobile devices
Click to view Web Link,click Chapter 6, Click Web Linkfrom left navigation, then click Flash Memory Cardsbelow Chapter 6
CompactFlash Smart Media Secure Digital
Memory Stick xD Picture Card
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Miniature Mobile Storage Media
What is a USB Flash Drive?
p. 236 Fig. 6-25 Next
Plugs in a USB port on a computer or mobile device
Storage capacities up to 4 GB Making the floppy disk
obsolete
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Miniature Mobile Storage Media
What is a smart card?
p. 237 Fig. 6-26 Next
Stores data on microprocessor embedded in small card
Input, process, output, and storage capabilities
Click to view Web Link,click Chapter 6, Click Web Linkfrom left navigation, then click Smart Cardsbelow Chapter 6
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Microfilm and Microfiche
What are microfilm and microfiche?
p. 238 Fig. 6-27 Next
Images recorded using Images recorded using computer output microfilm computer output microfilm
recorderrecorder
Store microscopic images of Store microscopic images of documents on roll or sheet of documents on roll or sheet of
filmfilm
Microfilm — 100- to215-foot roll of film
Microfiche — small sheet of film, usually 4” 6”
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Microfilm and Microfiche
How do life expectancies of various media compare?
p. 238 Fig. 6-28 Next
Microfilm and microfiche have longest life of any storage media
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Putting It All Together
What are recommended storage devices for home users?
p. 239 Fig. 6-29 Next
160 GB hard disk Online storage CD or DVD drive Card reader/writer USB flash drive
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Putting It All Together
What are recommended storage devices for small office/home office (SOHO) users?
p. 239 Fig. 6-29 Next
250 GB hard disk Online storage CD or DVD drive External hard drive for backup USB flash drive
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Putting It All Together
What are recommended storage devices for mobile users?
p. 239 Fig. 6-29 Next
100 GB hard disk Online storage CD or DVD drive Card reader/writer Portable hard disk for backup USB flash drive, and/or 5 GB PC Card hard
disk
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Putting It All Together
What are recommended storage devices for power users?
p. 239 Fig. 6-29 Next
CD or DVD drive 500 GB hard disk Online storage Portable hard disk for backup USB flash drive
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Putting It All Together
What are recommended storage devices for large business users?
p. 239 Fig. 6-29 Next
Desktop computer250 GB hard diskCD or DVD driveSmart card readerTape driveUSB flash drive
Server or MainframeNetwork storage server40 TB hard disk systemCD-ROM or DVD-ROM serverMicrofilm or microfiche
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Summary of Storage
Internal hard disksInternal hard disks
Portable hard disksPortable hard disks
Floppy disksFloppy disks
Zip disksZip disks
CD-ROMsCD-ROMs
Recordable and rewritable CDsRecordable and rewritable CDs
DVD-ROMsDVD-ROMs
Recordable and rewritable DVDsRecordable and rewritable DVDs
TapeTape
PC CardsPC Cards
Flash memory cardsFlash memory cards
USB Flash DrivesUSB Flash Drives
Microfilm and microficheMicrofilm and microfiche
Chapter 6 Complete
Smart CardsSmart Cards